ACCURACY OF PHYSICAL WORKING CAPACITY (PWC170) IN ESTIMATING AEROBIC FITNESS IN CHILDREN

Physical working capacity, the workload at a heart rate of 170 bpm (PW C170), has been utilized as a marker of maximal oxygen uptake. The pre cision of PWC170 in predicting VO2max in children has not been fully e valuated. In this study, 35 children (18 boys and 17 girls, mean ages 10.5 and 9.9 years, respectively) underwent maximal cycle testing to a ssess the relationship between VO2max and PWC170. These measures corre lated closely in absolute terms (r=0.71 and 0.70 for girls and boys, r espectively), but the relationship was weaker when both were expressed per kg body weight (r=0.65 and 0.48, respectively). When VO2max was c alculated from the regression equation of VO2max versus PWC170, the me an error from measured VO2max was 3.4 ml.kg-1.min-1 (SD 2.5) for the g irls and 2.8 ml.kg-1.min-1 (SD 2.6) for the boys. These findings indic ate that although mean predictability of VO2max from PWC170 is good, t he variability is wide, with a 10-15% error at one standard deviation. PWC170 provides only a crude estimate of VO2max and should not be use d to predict individual maximal aerobic power.